radioactive element, named 1947, from Greek astatos "unstable" (see astatic) + chemical suffix -ine (2). So called for its short half-life and lack of stable isotopes. "The element appears not to have a stable form and probably does not exist in nature" [Flood, "Origin of Chemical Names"].

"figure used in printing and writing to indicate footnote, omission, etc.," late 14c., asterich, asterisc, from Late Latin asteriscus, from Greek asterikos "little star," diminutive of aster "star" (see astro-). As a verb from 1733.

1590s, "a constellation, a group of stars," from Greek asterismos "a marking with stars," from aster "star" (see astro-). Any grouping of stars, whether a constellation or not (though in modern use, usually the latter). The "Big Dipper" is an asterism, not a constellation.

"pertaining to the stars," c. 1600, from Late Latin astralis, from Latin astrum "star," from Greek astron (see astro-). Meaning "pertaining to supersensible substances" is from 1690s, popularized late 19c. in Theosophy.

late 14c., from astrology + -er (1). Drove out French import astrologein, which, had it survived, probably would have yielded *astrologian, as in Chaucer's "The wise Astrologen." Earliest recorded reference is to roosters as announcers of sunrise.

late 14c., from Latin astrologia "astronomy, the science of the heavenly bodies," from Greek astrologia "telling of the stars," from astron "star" (see astro-) + -logia "treating of" (see -logy).

Originally identical with astronomy, it had also a special sense of "practical astronomy, astronomy applied to prediction of events." This was divided into natural astrology "the calculation and foretelling of natural phenomenon" (tides, eclipses, etc.), and judicial astrology "the art of judging occult influences of stars on human affairs" (also known as astromancy, 1650s). Differentiation between astrology and astronomy began late 1400s and by 17c. this word was limited to "reading influences of the stars and their effects on human destiny."

coined 1929 in science fiction, popularized from 1961 by U.S. space program, from astro- + nautes "sailor" (see naval). French astronautique (adj.) had been coined 1927 by "J.H. Rosny," pen name of Belgian-born science fiction writer Joseph Henri Honoré Boex (1856-1940) on model of aéronautique, and Astronaut was used in 1880 as the name of a fictional spaceship by English writer Percy Greg (1836-1889) in "Across the Zodiac."

late 14c., from astronomy (q.v.), replacing French import astronomyen (c. 1300), which, had it survived, probably would have yielded *astronomian. Still in Shakespeare used in places where we would write astrologer.

1550s, from astronomy + -ical. Popular meaning "immense, concerning very large figures" (as sizes and distances in astronomy) is attested from 1899. Astronomical unit (abbreviation A.U.) "mean distance from Earth to Sun," used as a unit of measure of distance in space, is from 1909. Related: Astronomically.

1966, proprietary name for a kind of artificial grass, so called because it was used first in the Houston, Texas, Astrodome, indoor sports stadium. See astro- + turf. Houston was a center of the U.S. space program.

early 15c., earlier asile (late 14c.), from Latin asylum "sanctuary," from Greek asylon "refuge," noun use of neuter of asylos "inviolable, safe from violence," especially of persons seeking protection, from a- "without" + syle "right of seizure." So literally "an inviolable place." General sense of "safe or secure place" is from 1640s; meaning "benevolent institution to shelter some class of persons" is from 1776.

1680s; see asymmetry + -ical. Other forms that have served as an adjective based on asymmetry are asymmetral (1620s), asymmetrous (1660s), and asymmetric (1875); only the last seems to have any currency. Related: Asymmetrically.